Many portable electronic devices contain ambient light sensors to sense ambient light of the area surrounding the electronic device. The output of these sensors may be utilized by the device to control the brightness of the backlighting of a display or keyboard in response to ambient light. For example, the device may use the ambient light detected by an ambient light sensor to adjust the brightness of an LCD screen of a laptop computer to maintain a relatively uniform appearance under all lighting conditions, from darkness to direct sunlight. Adjusting the brightness of the backlighting of an electronic device may also save battery power, as backlighting often consumes large amounts of battery power. Thus, dimming the backlights of an electronic device may offer both power savings and uniform appearance.
The output of the ambient light sensor may also be utilized to control certain lights or luminance effects associated with an electronic device other than the backlighting. For example, many electronic devices contain indicator lights that provide to the user information about the device, such as the operating status. However, in lowlight environments such as a dark room, indicator lights may appear very bright if the luminance of the lights are not adjusting based on the ambient light in the room. Thus, an ambient light sensor may also be located on the outer shell of the electronic device to measure the ambient light and aid in controlling the indicator lights of the outer shell accordingly when the electronic device is in the closed position.
Generally, the best place for locating an ambient light sensor on an electronic device is near the illuminator being controlled (e.g. the display or indicator lights) and facing the direction where the ambient light originates. This allows the ambient light sensor to accurately sense the ambient light of the room or surrounding area in order to allow the device to adjust the brightness of the illuminator accordingly. For example, an ambient light sensor utilized in controlling an LCD screen of a laptop computer may be placed on the bezel of the computer, facing the user. This position would provide the optimal location for the ambient light sensor to detect the amount of ambient light falling on the display such that the device may control the brightness of the LCD screen accordingly.
Similarly, the best place to locate an ambient light sensor associated with controlling illuminators located on the outer shell of an electronic device would be next the illuminators on the outer shell. This allows the ambient light sensor to accurately sense the ambient light of the room or surrounding area in order to allow the device to adjust the brightness of the illuminators located on the outer shell of the device accordingly.